Formal Methods for Conformance Testing: Theory Can Be Practical!

Although testing is the most widely used technique to control the quality of software systems, it is a topic that, until relatively recently, has received scant attention from the computer research community. Although some pioneering work was already done a considerable time ago [Cho78,GG83,How78,Mye79], the testing of software systems has never become a mainstream activity of scientific research. The reasons that are given to explain this situation usually include arguments to the effect that testing as a technique is inferior to verification -testing can show only the presence of errors, not their absence - and that we should therefore concentrate on developing theory and tools for the latter. It has also been frequently said that testing is by its very nature a non-formal activity, where formal methods and related tools are at best of little use.